Hydraulic crowd for shovel



April 2, 1968 T; LEARMONT ET AL HYDRAULIC cRowD FOR sHovEL E Sheets-Sneet l Filed July 7, 1966 INVENTORS LEARMONT THEODORE M.W|LLGP\UBS BY V@ TOM ATTORNEY April 2, 1968 -r LEARMONT ET A!- HYDRAULIC CROWD FOR SHOVEL 2 Sheets-Sne Filed July 7, 1966 United States Patent() ABSTRACT OF THE DISCLOSURE The crawler-mounted power shovel has a boom projecting from the front of its revolving frame and supported at the top by cables from an A-frame. A saddle block is pivotally mounted on the boom to support a tubular dipper handle for reciprocating crowd movement. A tubular crowd frame projects rearwardly from the saddle block. A double acting hydraulic ram has its cylinder endmounted inside the dipper handle and its piston rod anchored to the back end of the crowd frame to crowd the dipper handle. Fluid is pumped to and from the cylinder through the piston rod.

The present invention relates to an excavator, and more particularly the invention resides in an excavator, which has a boom and asaddle block pivotally mounted on said boom and a dipper handle slidably mounted in said saddle block, wherein an hydraulic ram anchored at one end to said saddle block and fastened at its opposite end to said dipper handle provides a crowd mechanism for said excavator.

In the past, excavators have generally used a drum and cable crowd mechanism which had, as a chief disadvan` tage, the maintenance and cost problem resulting from cable wear and cable break. The present invention makes it possible to eliminate the costly and cumbersome drum and cable crowd mechanism, and with it, all of its attenuating disadvantages. This is achieved by the use of an hydraulic ram crowd mechanism. In addition to eliminating the disadvantage of the drum and cable crowd mechanism, the present invention drastically reduces the poten- `tial for hydraulic breakdowns and greatly simplilies such maintenance of the hydraulic ram as cannot be avoided.

`These advantages are accomplished by `mounting the hydraulic ram at its ends only, so that the cylinder is fastened to move with the dipper handle, and the piston rod is anchored to the saddle block, and then by feeding the hydraulic Huid to the cylinder through the piston rod.

Accordingly, the salient objects and advantages of the present invention may be summarized as follows:

To provide the advantages of direct hydraulic drive to the crowd mechanism of an excavator;

To eliminate the disadvantages of the drum and cable crowd mechanism;

To provide an hydraulic crowd mechanism wherein the potential for hydraulic failure is minimized;

To provide an hydraulic crowd mechanism that is readily accessible for routine maintenance;

To provide a highly eicient hydraulic crowd mechamsm;

To provide in an excavator a crowd mechanism that minimizes maintenance costs; and

To provide a very compact crowd mechanism for an excavator.

The foregoing and other advantages of the present invention are manifest in the following description of the best mode presently contemplated for embodying the invention. This preferred embodiment is set forth clearly and concisely and in suicient detail so that anyone skilled in the art may learn to practice this invention, but

it must be understood that the invention is not limited to v the preferred embodiment. In contrast to the preferred embodiment described, the subject matter considered to be the invention is set forth in the claim appearing at the end of this specification.

In the drawings:

FIG. 1 is a side elevation of an excavator embodying the present invention,

FIG. 2 is an enlarged side elevation of the dipper handle, saddle block and part of the crowd mechanism of the excavator shown in FIG. 1, and

FIG. 3 is a side elevation partially in section of the dipper handle shown in FIG. 2 illustrating partially in section the hydraulic crowd ram within the dipper handle.

Referring to FIG. 1 of the drawings, there is shown a mobile, self-propelled excavator 1 which has a turntable 2 rotatably mounted on a crawler truck 3. The turntable 2 supports a cab 4 which houses the operator, power plant and controls of the excavator. The turntable 2 also supports an A-frarne 5 mounted toward the back end, and a boom 6, which has its bottom end 7 pivotally mounted at the front end of the turntable 2. The boom 6 is made of two, parallel, spaced apart, structural members. Boom cables 8 extend from the top of the A-frame 5 to the top of the boom 6 to support the top 9 of the boom 6.

A powered hoist drum 10 is mounted on the turntable 2 and has one end of a hoist cable 11 wound on it. The hoist cable '11 passes over a sheave 12 journaled in the top 9 of the boom 6, and down to be attached to a bail 13 on a dipper 14. Thus, as the hoist drum 10 reels in the hoist cable 11, the dipper 14 is elevated and as the hoist drum 10 feeds out the hoist cable 11, the dipper 14 is lowered.

The dipper 14 is mounted on the front end of a cylindrical, tubular dipper handle 15, which is mounted for rectilinear reciprocating movement in a saddle block 16. The hollow dipper handle 15 contains an hydraulic crowd ram 17. The hydraulic crowd ram 17 is a double acting ram made up of a cylinder 18 with a reciprocable piston 19 inside of it, and a hollow piston rod 20 projects rearwardly from the piston 19 and out of the cylinder 18 through a sliding sealing member 21 in the rear end 22 of the cylinder 1S. An eye 23 projecting from the front end 24 of the cylinder is pivotally mounted about a pin 25 spanning the interior of the front end of the hollow dipper handle 15. v

A rigid tube 26 for hydraulic Huid extends axially the full length of the interior of the piston rod 20 and at its front end it communicates with a fluid passageway 27 passing axially through the piston '19 to open into the cylinder chamber 28 in front of the piston 19. The outside of the tube 26 and the inside of the piston. rod 20 define an annular hydraulic Huid passage 29 through the length of the piston rod 20. The annular passage 29 opens intoa cylinder chamber 30 behind the piston 19 through ducts 31 through the walls in the frontend of the hollow piston rod 20.

The saddle block 16 is made up of a yoke 32 and a crowd frame 33 mounted on the back end of the yoke 32 and extending rearwardly therefrom. The yoke 32 has two annular, spaced apart, sliding bearing members 34 and 35 through which the dipper handle 15 is slidably supported, and the bearing members 34 and 35 are supported by a main beam 36 which has its respective ends joined to the bottoms of the bearing members 34 and 35. Trunnions 37 project laterally from each side of the main beam 36 and are journaled in bushings in the parallel structural members of the boom 6. The crowd frame 33 is comprised of a cylindrical tubular structural member 38 extending rearwardly from the yoke 32 and a crowd anchor piece 39 in the form of a cap on the rear end of the structural member 38. The crowd anchor piece 39 has 3 an anchor pin 40 mounted transversely through it, and it has access openings through the back The hydraulic uid tube 26 and the annular fluid passageway 29 open through ducts 41 in an enlarged portion 42 at the rear end of the piston rod 20. The enlarged portion 42 on the end of the piston rod terminates in an eye 43 which is anchored to the crowd anchor piece 39 by the anchor pin 40.

To drive the hydraulic crowd ram 17, an hydraulic system is provided, which is the subject of a copending application Ser. No. 611,633, tiled Jan. 25, 1967, by the same inventors plus William H. Smith, and assigned to the same assignee as the present application, and for a detailed description of the hydraulic system, reference may be made to that application. Suflceit for the purposes of this disclosure to mention that a prime mover 44 drives hydraulic pumps 45, Which pump hydraulic fluid between a reservoir (not shown) and the hydraulic crowd ram 17. The hydraulic fluid is pumped from the pumps 45 through flexible conduits 46 to a manifold block 47 and then through a rigid conduit 48 and a rotatable coupling 49 to a second manifold block 50. From the second manifold block 50, the uid flows through flexible conduits -1 through a third manifold block 52 and through a second rigid conduit 53 to a lock valve 54. The fluid then flows from the manifold block 54 through ilexible conduits 55 into the crowd anchor piece 39 to be coupled to the ducts 41 in the enlarged end portion 42 of the piston rod 20. The same hydraulic conduits 55, 53, 51, 48 and 46 conduit hydraulic iluid both to and from the pumps 45 and reservoir (not shown).

To operate the crowd mechanism to extend the dipper outwardly, or forwardly, hydraulic uid is pumped by the pumps 45 from the reservoir (not shown), through the hydraulic conduits 46, 48, 51, 53 and 55, manifold blocks 47, 50, 52 and 54, and rotatable coupling 49 (hereafter called the hydraulic system) and thence through the iluid tube 26 inside the piston rod 20 and through the passageway 27 in the piston 19 to the cylinder chamber 28 (hereafter called the front cylinder chamber 28) in front of the piston 19. Simultaneously hydraulic iluid is pumped from the cylinder chamber 30 (hereafter called the back cylinder chamber 30) behind the piston 19 through the ducts 31 in the piston rod 20 and the annular passage 29 back into the hydraulic system. Conversely, to draw the dipper 14 back, hydraulic uid is simultaneously pumped out of the front cylinder 28 into the hydraulic system, and out of the hydraulic system into the back cylinder chamber 3). The piston 19 and piston rod 20 remain stationary relative to the saddle block 16, while the cylinder 18 moves and carries the dipper handle '15 with it throughout the reciprocating crowd operations.

Since the forward crowd movement usually requires the greatest force, the present invention provides the greatest mechanical advantage for movement in that direction by having the front cylinder chamber 2S perform that work. The front cylinder chamber 28 has approximately twice as much volume as the back cylinder chamber 30 for any given linear movement of the piston 19, because of the presence of the piston rod in the back cylinder chamber. Therefore, any iluid pressure in the front cylinder chamber 28 will effect much greater crowd force than the same fluid pressure in the back cylinder chamber 30.

Play develops between the sliding bearings 34 and 35 and the dipper handle 15, permitting the latter to deflect downward under load. This deflection of the dipper handle 15 is isolated from the hydraulic crowd ram 17 by mounting the ram only at its ends and providing clearance between the inside of the dipper handle 15 and the ram 17. Thus, the ram 17 is protected from damage. Also, if the ram 17 were connected to the hydraulic system by external conduits, instead of through the piston rod 20, such external conduits could be pinched and broken between the ram 17 and dipper handle 15 when the latter is deilected. Additionally, by connecting the ram l17 to the hydraulic system at the enlarged end 42 of the piston rod 20 anchored to the crowd anchor piece 39 at the back end of the crowd frame 33, when the packing in the sliding seal 21 of the ram 17 requires maintenance, it will be conveniently accessible through the back of the crowd anchor piece 39.

The foregoing description and drawings illustrate one possible embodiment of the invention. By substituting equivalents, introducing different obvious variations, and eliminating environmental structure described above, a multitude of dilerent embodiments can be contrived. Accordingly, the subject matter considered to be the invention is not limited to the described embodiment, but is set forth in the following claim.

We claim:

1. In a power shovel, the combination comprising a boom support means;

a boom supported at its top and bottom ends by said boom support means;

a saddle block pivotally mounted on said boom intermediate the ends of said boom, having a yoke means for slidably supporting a dipper handle, and having a crowd support frame projecting rearwardly from said yoke means;

a dipper handle mounted for reciprocating crowd movement in said saddle block, and having a hollow interior open at its rearward end;

a hydraulic crowd ram having a cylinder mounted in said hollow interior of said dipper handle with its blind end extending forwardly, and having a piston rod on its piston projecting from said open rearward end of said dipper handle with the end of said piston rod anchored to said crowd support frame projecting rearwardly from said yoke means on said saddle block;

and fluid passageways extending axially through said piston rod to carry fluid to and from both sides of said piston to impart reciprocating crowd movement to said dipper handle and said cylinder mounted in said dipper handle, said fluid passageways issuing from said end of said piston ro anchored to said crowd support frame.

References Cited UNITED STATES PATENTS 227,222 4-/1880 Dill 214-137 655,758 8/1900 Cheney et al 214-135 2,791,341 5/1957 Michaels et al 214--141 2,984,373 5/1961 Przybyski 214-141 3,045,844 7/1962 Learmont et al 214-135 HUGO O. SCHULZ, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,375 ,943 April Z 1968 Tom Learmont et al.

in the above identified It is certified that error appears hereby corrected as patent and that Said Letters Patent are shown below:

Column l, lines 38 and 39, "attenuating" should read attending -w line 4l, "disadvantage" should read disadvantages Column 3, line 30, "Conduit" should read Conduct w. Column 4, line 53, "To" should read Tod Signed and sealed this 12th day of August 1969.

(SEAL) Attest:

Edward M. Fletcher, J r.

Commissioner of Patents Attesting Officer WILLIAM E. SCHUYLER, JR. 

